Change spec/shared submodule to use https (#2201)

Co-authored-by: Oleg Pudeyev <[email protected]>

Author: p-mongo

.gitmodules

@@ -3,4 +3,4 @@
 	url = https://github.com/mongodb-labs/drivers-evergreen-tools
 [submodule "spec/shared"]
 	path = spec/shared
-	url = git@github.com:mongodb-labs/mongo-ruby-spec-shared
+	url = https://github.com/mongodb-labs/mongo-ruby-spec-shared